Turnstiles have long been known. Commonly they involve a gate which rotates only in one direction about an axis, operating in co-operation with an adjacent barrier. They permit passage of persons or animals in one direction only. Turnstiles are known with internal gearing, coin or ticket operation, mechanical detents, and the like.
Children often enjoy playing with turnstiles. In some instances children try to spin the turnstile as quickly as they can, and may injure themselves with or in the rotating structure. In particular, children may be prone to climb upon, and trap themselves between, the rotating pans of the turnstile and an adjacent barrier. The turnstile can only turn in one direction, so it can only become more tightly jammed as a child struggles.
Presently known turnstiles may be released by use of electric solenoids to disengage an internal gear mechanism, or by swinging the entire turnstile out of the way.
One type of common turnstile employs a solid machined block fit into the top of a hollow support column. The machined block is adapted to seat a pair of one way roller or needle bearings such that the rotating member can only turn in one direction. This embodiment has several disadvantages. First, the turnstile cannot be adapted to turn in the opposite direction without major disassembly to permit the block and bearings to be installed in the opposite direction. Second, the bearings may be inadequately suited to eccentric loads applied, for example, when adults place extreme force on the arms of the turnstile. Third there is no emergency release. If a child is jammed in the bars it may be necessary to unbolt the entire assembly from the floor. Fourth, the block is held in the shaft by a single screw. Over time the block may begin to shift back and forth in the shaft, rotating about the axis of the screw.
As turnstiles are often used by children as toys they are often subject to abuse. Thus them is a need for a safety turnstile which may be easily released, may turn in either direction, will resist high speed spinning, and which is sufficiently rugged to survive moderately abusive treatment.
Further examples of prior an for turnstiles include U.S. Pat. No. 5,072,543 which relates to a turnstile made with a stationary turnstile support shaft extending from a solid support, and a bearing on the end of the shaft. The turnstile hub is supported on the end of the shaft with a bearing. The turnstile hub is locked against rotation in a fee-paid direction by a unidirectional pawl that engages a cutout on a ratchet plate attached to the hub. The unidirectional pawl is released by energizing a solenoid latching mechanism.
In addition, U.S. Pat. No. 3,978,613 relates to a turnstile mechanism comprising a rotatable hub adapted to be driven by a person using a turnstile, the hub being connected to (or incorporating) a disc formed with a number of stop surfaces which are engageable by a stop member which is movable between a first position clear of the path of the stop surfaces and a second position lying in the path of the stop surfaces.
Further, U.S. Pat. No. 3,914,902 relates to a turnstile which includes a turnstile head pivotally mounted on a support for rotation about an axis defined by the support. A shaft is journaled in the turnstile head and a hub is keyed to the shaft for the rotation thereof responsive to the rotation of the hub. Arms carried by the hub radiate therefrom in a conical formation, and when indexed in the home position, one of the arms is disposed in a substantially horizontal passage barring position while the remaining arms are disposed in a substantially vertical position. A spur gear is keyed to the shaft at the end thereof opposite the end portion to which the hub is keyed and is in meshed relationship with a pinion gear which is journaled in the turnstile head and which is provided with a roller clutch which allows for rotation of the pinion gear in a single direction only. Three depending roller cams are disposed about the periphery of the spur gear which is aligned on the shaft so that the roller cams are substantially radially aligned with the extending arms carried by the hub.
U.S. Pat. No. 3,383,797 relates to a turnstile utilizing a cam controlled assembly.